Organic light emitting display apparatus and method of manufacturing the organic light emitting display apparatus

ABSTRACT

An organic light emitting display apparatus includes a substrate; a thin film transistor which is disposed over the substrate; a first electrode which is disposed over the substrate and electrically connected to the thin film transistor; a passivation layer which covers the thin film transistor and contacts a predetermined region of an upper surface of the first electrode; an intermediate layer which is disposed over the first electrode, includes an organic emission layer, and contacts a predetermined region of the passivation layer; and a second electrode which is disposed over the intermediate layer.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims the benefit of Korean Patent Application No.10-2010-0138038, filed on Dec. 29, 2010, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein in itsentirety by reference.

BACKGROUND

1. Field

The present disclosure relates to an organic light emitting displayapparatus and a method of manufacturing the organic light emittingdisplay apparatus, and more particularly, to an organic light emittingdisplay apparatus providing an improved image quality.

2. Description of the Related Technology

Display apparatuses have been recently being replaced by thin flat paneldisplay apparatuses that are portable. Organic light-emitting displayapparatuses from among flat panel display apparatuses are self-emissiondisplay apparatuses and have a larger viewing angle, better contrastcharacteristics, and a faster response rate than other displayapparatuses, and thus have drawn attention as a next-generation displayapparatus.

Organic light emitting display apparatuses have an intermediate layer, afirst electrode, and a second electrode. The intermediate layer includesan organic emission layer, and generates visible light when the firstelectrode and the second electrode are supplied with a voltage.

Since it is not easy for the visible light generated by the intermediatelayer to have uniform characteristics, organic light-emitting displayapparatuses have a limit in improving the image quality.

SUMMARY

An aspect of the present invention provides an organic light emittingdisplay apparatus capable of easily improving image qualitycharacteristics, and a method of manufacturing the organic lightemitting display apparatus.

According to an aspect of the present invention, there is provided anorganic light emitting display apparatus comprising a substrate; a thinfilm transistor which is disposed over the substrate; a first electrodewhich is disposed over the substrate and electrically connected to thethin film transistor; a passivation layer which covers the thin filmtransistor and contacts a predetermined region of an upper surface ofthe first electrode; an intermediate layer which is disposed over thefirst electrode, comprises an organic emission layer, and contacts apredetermined region of the passivation layer; and a second electrodewhich is disposed over the intermediate layer.

An edge region of the intermediate layer may be separated from the firstelectrode.

The passivation layer may comprise a protrusion that contacts the firstelectrode, and the protrusion may be disposed between the intermediatelayer and the first electrode so that the edge region of theintermediate layer is separated from the first electrode.

The passivation layer may comprise an inorganic material.

The passivation layer may comprise an oxide or a nitride.

The organic light emitting display apparatus may further comprise apixel defining layer which is disposed over the passivation layer,wherein the pixel defining layer is separated from the intermediatelayer.

The pixel defining layer may comprise an organic material.

The pixel defining layer may have a width smaller than that of thepassivation layer so as not to overpass an edge of the passivationlayer.

The thin film transistor may comprise an active layer, a gate electrodeinsulated from the active layer, a source electrode, and a drainelectrode. The first electrode may be electrically connected to thedrain electrode.

A gate insulating layer may be disposed between the active layer and thegate electrode, and an interlayer insulating layer may be disposedbetween the gate electrode and the source electrode and between the gateelectrode and the drain electrode. The gate insulating layer and theinterlayer insulating layer may be covered with the passivation layerwithout extending beyond the boundary of the passivation layer.

The drain electrode and the first electrode may be connected to eachother by a connection portion.

The connection portion may be formed of a material same as a materialused to form the source electrode or the drain electrode.

The first electrode may contact the substrate.

According to another aspect of the present invention, there is provideda method of manufacturing an organic light emitting display apparatus,the method comprising forming a thin film transistor and a firstelectrode electrically connected to the thin film transistor, over thesubstrate; forming a passivation layer which covers the thin filmtransistor and contacts a predetermined region of an upper surface ofthe first electrode; forming an intermediate layer over the firstelectrode, the intermediate contacting a predetermined region of thepassivation layer and comprising an organic emission layer; and forminga second electrode over the intermediate layer.

The method may further comprise forming a pixel defining layer over thepassivation layer, wherein the pixel defining layer is separated fromthe intermediate layer, and disposed between the passivation layer andthe second electrode. The forming of the passivation layer may comprisedepositing a material used to form the passivation layer, and patterningthe material by using the pixel defining layer as a mask.

The method may further comprise performing a plasma processing processafter forming the pixel defining layer and before forming theintermediate layer.

The forming of the thin film transistor may comprise forming an activelayer separated from the first electrode, over the substrate; forming agate electrode insulated from the active layer; and forming a sourceelectrode and a drain electrode which are separated from the gateelectrode and are connected to a predetermined region of the activelayer.

The forming of the thin film transistor may further comprise forming agate insulating layer between the active layer and the gate electrode soas to cover a predetermined region of the first electrode; and formingan interlayer insulating layer between the gate electrode and the sourceelectrode and between the gate electrode and the drain electrode. Thepassivation layer may cover the gate insulating layer and the interlayerinsulating layer so that the gate insulating layer and the interlayerinsulating layer does not extend the boundary of the passivation layer.

The intermediate layer may be formed by printing.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present inventionwill become more apparent by describing in detail embodiments thereofwith reference to the attached drawings in which:

FIG. 1 is a schematic cross-sectional view of an organic light emittingdisplay apparatus according to an embodiment of the present invention;and

FIGS. 2A through 2I are cross-sectional views for describing a method ofmanufacturing an organic light emitting display apparatus, according toan embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present invention are described morefully with reference to the accompanying drawings, in which embodimentsof the invention are shown.

FIG. 1 is a schematic cross-sectional view of an organic light emittingdisplay apparatus 100 according to an embodiment of the presentinvention.

Referring to FIG. 1, the organic light emitting display apparatus 100includes a substrate 101, a thin film transistor TFT, a first electrode110, a passivation layer 109, an intermediate layer 112, and a secondelectrode 113. The thin film transistor TFT includes an active layer102, a gate electrode 104, a source electrode 106, and a drain electrode107.

Compositions of the respective components of the organic light emittingdisplay apparatus 100 are described in detail hereinafter.

The substrate 101 may be formed of a transparent glass materialcontaining SiO₂ as a main component. However, the present invention isnot limited thereto, and the substrate 101 may be formed of atransparent plastic material. The plastic material used to form thesubstrate 101 may be an organic insulating material selected from thegroup consisting of polyethersulphone (PES), polyacrylate (PAR),polyetherimide (PEI), polyethyelenen napthalate (PEN),polyethyeleneterepthalate (PET), polyphenylene sulfide (PPS),polyallylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC),and cellulose acetate propionate (CAP).

The thin film transistor TFT and the first electrode 110 are formed onthe substrate 101. The thin film transistor TFT and the first electrode110 are electrically connected to each other. The thin film transistorTFT includes the active layer 102, the gate electrode 104, the sourceelectrode 106, and the drain electrode 107.

The thin film transistor TFT and the first electrode 110 are describedin detail hereinafter.

An active layer 102 having a predetermined pattern is formed on thesubstrate 101. The active layer 102 may be formed of an inorganicsemiconductor material, such as amorphous silicon or polysilicon, or anorganic semiconductor material. The active layer 102 includes a sourceregion, a drain region, and a channel region between the source anddrain regions.

The first electrode 110 is formed on the substrate 101 at a positionspaced from the active layer 102, and separated from the active layer102.

A gate insulating layer 103 is formed on the active layer 102. The gateinsulating layer 103 covers a predetermined region of the firstelectrode 110.

The gate electrode 104 is formed on a predetermined region of the uppersurface of the gate insulating layer 103. The gate electrode 104 isconnected to a gate line (not shown) that applies a TFT ON/OFF signal.The gate electrode 104 may be formed of metal or a metal alloy such asgold (Au), silver (Ag), copper (Cu), nickel (Ni), platinum (Pt),palladium (Pd), aluminum (Al), molybdenum (Mo), an Al:neodymium (Nd)alloy, an Mo:tungsten (W) alloy, or the like, but the present inventionis not limited thereto.

An interlayer insulating layer 105 is formed on the gate electrode 104.The interlayer insulating layer 105 exposes source and drain regions ofthe active layer 102. The source electrode 106 and the drain electrode107 are formed to contact the exposed source and drain regions,respectively, of the active layer 102.

The drain electrode 107 is electrically connected to the first electrode110 by a connection portion 108. In detail, after the gate insulatinglayer 103 and the interlayer insulating layer 105 are formed so that apredetermined region of the first electrode 110 is exposed, theconnection portion 108 is formed on the exposed predetermined region ofthe first electrode 110. The connection portion 108 may be formed of thesame material as a material used to form the source electrode 106 or thedrain electrode 107.

The passivation layer 109 is formed to cover the thin film transistorTFT. The passivation layer 109 includes a protrusion 109 a. Theprotrusion 109 a protrudes from a lateral surface of the passivationlayer 109. The protrusion 109 a contacts the first electrode 110.

The passivation layer 109 covers the interlayer insulating layer 105 andthe gate insulating layer 103. Accordingly, the gate insulating layer103 and the interlayer insulating layer 105 do not extend beyond theboundary of the passivation layer 109. The passivation layer 109contains an inorganic material, for example, an oxide or a nitride. Indetail, the passivation layer 109 may contain silicon oxide or siliconnitride.

A pixel defining layer 111 is formed on the passivation layer 109. Thepixel defining layer 111 is formed not to overpass the edge of thepassivation layer 109. In other words, the pixel defining layer 111 isformed to have a width smaller than that of the passivation layer 109.The pixel defining layer 111 is spaced apart from the first electrode110. The pixel defining layer 111 contains an organic material.

The intermediate layer 112 is formed on the first electrode 110. Theintermediate layer 112 includes an organic emission layer (not shown)that emits visible light. The intermediate layer 112 may be formed byusing any of various methods, for example, a printing method.

The intermediate layer 112 is spaced apart from the pixel defining layer111. An edge region 112 a of the intermediate layer 112 is spaced apartfrom the first electrode 110. In other words, the protrusion 109 a ofthe passivation layer 109 is disposed between the edge region 112 a ofthe intermediate layer 112 and the first electrode 110, so that the edgeregion 112 a is separated from the first electrode 110.

The second electrode 113 is formed on the intermediate layer 112. Thesecond electrode 113 may be formed on the entire regions of theintermediate layer 112 and the pixel defining layer 111. When a voltageis applied via the first electrode 110 and the second electrode 113, theorganic emission layer of the intermediate layer 112 emits visiblelight.

A sealing member (not shown) may be disposed on the second electrode113. The sealing member is formed to protect the intermediate layer 112and the other layers from external moisture, oxygen, or the like, and isformed of a transparent material. To this end, the sealing member mayinclude glass or plastic or have a structure in which an organicmaterial and an inorganic material are stacked in multiple layers.

In the organic light emitting display apparatus 100 according to thepresent embodiment, the edge region 112 a of the intermediate layer 112is separated from the first electrode 110 via the protrusion 109 a ofthe passivation layer 109. In a display panel, for example, the edgeregion of an intermediate layer sometimes has abnormal electricalcharacteristics, and thus an image quality is not uniform. However, inan embodiment of the present invention, since the edge region 112 a ofthe intermediate layer 112 is separated from the first electrode 110,the edge region 112 a of the intermediate layer 112 is prevented fromhaving abnormal electrical characteristics. Consequently, the entireregion of the intermediate layer 112 may provide a uniform imagequality.

In addition, in the organic light emitting display apparatus 100according to the present embodiment, the first electrode 110 is formedon the substrate 101. The visible light generated by the intermediatelayer 112 may show variable optical characteristics while passingthrough various layers. Thus, optical characteristics sensible by usersmay be reduced. In the present embodiment, no insulating layers existbetween the first electrode 110 and the substrate 101. Accordingly,light traveling toward the substrate 101 from among the visible lightgenerated by the intermediate layer 112 is not interfered with otherinsulating layers or not lost. In particular, when the organic lightemitting display apparatus 100 is of bottom emission type, that is, whenthe organic light emitting display apparatus 100 is an apparatus inwhich the visible light generated by the intermediate layer 112 isrecognized by a user through the substrate 101, the visible lightgenerated by the intermediate layer 112 is recognized by the userwithout being lost due to interference, resonance, or the like. Thus,the image quality of the organic light emitting display apparatus 100 isimproved.

When the pixel defining layer 111 is formed on the passivation layer109, the pixel defining layer 111 is formed to be separated from thefirst electrode 110, thereby preventing bad patterning and non-uniformformation of the intermediate layer 112. In other words, when theintermediate layer 112 is formed on the first electrode 110 duringpatterning of the intermediate layer 112, the intermediate layer 112 iseasily prevented from contacting the pixel defining layer 111.

In a display panel, for example, when an intermediate layer contacts alateral surface of a pixel defining layer, a difference between thethicknesses of a portion close to the pixel defining layer and a portionspaced away from the pixel defining layer among the region of theintermediate layer increases. Thus, improving emission properties is noteasy due to the non-uniform thickness of the intermediate layer. This isbecause contact between the intermediate layer and the pixel defininglayer is significantly different from contact between the intermediatelayer and a first electrode. In particular, when the surfaces of thefirst electrode and the pixel defining layer are processed using plasmaor the like before the formation of the intermediate layer, thenon-uniformity of the thickness of the intermediate layer increases.However, in embodiments of the present invention, the pixel defininglayer 111 is disposed on the upper surface of the passivation layer 109and the intermediate layer 112 is spaced apart from the pixel defininglayer 111, thereby preventing the thickness of the intermediate layer112 from being non-uniform. In particular, the passivation layer 109contains an inorganic material, and thus more easily contacts theintermediate layer 112 than the pixel defining layer 111.

FIGS. 2A through 2I are cross-sectional views for describing a method ofmanufacturing the organic light emitting display apparatus 100,according to an embodiment of the present invention. The componentsshown in FIGS. 2A through 2I are the same as the components shown inFIG. 1. The method is described with reference to FIGS. 2A through 2Ihereinafter.

Referring to FIG. 2A, the active layer 102 having a predeterminedpattern is formed on the substrate 101. The active layer 102 may beformed of an inorganic semiconductor material, such as amorphous siliconor polysilicon, or an organic semiconductor material. The active layer102 includes a source region, a drain region, and a channel regionbetween the source and drain regions.

Referring to FIG. 2B, the first electrode 110 is formed on the substrate101 at a position spaced from the active layer 102, and separated fromthe active layer 102. The first electrode 110 contains a transmissiveconductive material. In detail, the first electrode 110 contains ITO.Although the first electrode 110 is formed after the formation of theactive layer 102 in the present embodiment, the present invention is notlimited thereto. In other words, the active layer 102 may be formedafter the first electrode 110 is formed.

Thereafter, referring to FIG. 2C, a first insulating material layer 103a used to form the gate insulating layer 103 is formed on the activelayer 102 and the first electrode 110. Various materials may be used toform the first insulating material layer 103 a.

Thereafter, referring to FIG. 2D, the gate electrode 104 is formed on apredetermined region of the upper surface of the first insulatingmaterial layer 103 a so as to be overlapped with the active layer 102.The gate electrode 104 is insulated from the active layer 102 by thefirst insulating material layer 103 a.

Thereafter, referring to FIG. 2E, a second insulating material layer 105a used to form the interlayer insulating layer 105 is formed on the gateelectrode 104.

Thereafter, referring to FIG. 2F, the gate insulating layer 103 and theinterlayer insulating layer 105 are formed by patterning the first andsecond insulating material layers 103 a and 105 a, respectively. Asource contact hole CS, a drain contact hole CD, a connection hole CP,and a via hole V are formed in the gate insulating layer 103 and theinterlayer insulating layer 105.

The source contact hole CS and the drain contact hole CD are formed toexpose predetermined regions of the active layer 102. The sourceelectrode 106 and the drain electrode 107 are connected to the sourcecontact hole CS and the drain contact hole CD through a subsequentprocess.

The connection hole CP and the via hole V are formed to exposepredetermined regions of the first electrode 110. The intermediate layer112 is formed in the via hole V through a subsequent process.

The first insulating material layer 103 a and the second insulatingmaterial layer 105 a may be patterned simultaneously. This results inthe improvement of process convenience.

Thereafter, referring to FIG. 2G, the source electrode 106 and the drainelectrode 107 are formed to contact the exposed regions of the activelayer 102, thereby completing the formation of the thin film transistorTFT. The thin film transistor TFT includes the active layer 102, thegate electrode 104, the source electrode 106, and the drain electrode107.

In one embodiment, referring to FIG. 2G, the source electrode 106 isformed to correspond to the source contact hole CS, and the drainelectrode 107 is formed to correspond to the drain contact hole CD.

The connection portion 108 is formed to correspond to the connectionhole CP. The connection portion 108 is also connected to one end of thedrain electrode 107. The drain electrode 107 is electrically connectedto the first electrode 110 by the connection portion 108.

The connection portion 108 may be formed of the same material as amaterial used to form the source electrode 106 or the drain electrode107. In detail, the source electrode 106, the drain electrode 107, andthe connection portion 108 may be formed of the same material, and maybe formed by one patterning process.

Thereafter, referring to FIG. 2H, the passivation layer 109 is formed soas to cover the thin film transistor TFT, and the pixel defining layer111 is formed on the passivation layer 109. The passivation layer 109includes the protrusion 109 a, and the protrusion 109 a protrudes fromthe lateral surface of the passivation layer 109. The protrusion 109 acontacts the first electrode 110.

The passivation layer 109 covers the interlayer insulating layer 105 andthe gate insulating layer 103. Accordingly, the gate insulating layer103 and the interlayer insulating layer 105 do not extend beyond thepassivation layer 109. The passivation layer 109 contains an inorganicmaterial, for example, an oxide or a nitride. In detail, the passivationlayer 109 may contain silicon oxide or silicon nitride.

The pixel defining layer 111 is formed not to overpass the edge of thepassivation layer 109. The pixel defining layer 111 is spaced apart fromthe first electrode 110. The pixel defining layer 111 contains anorganic material.

A method of forming the passivation layer 109 and the pixel defininglayer 111 is described in detail hereinafter. First, in one embodiment,a material used to form the passivation layer 109 is deposited on theTFT without patterning, and then a material used to form the pixeldefining layer 111 is deposited on the material used to form thepassivation layer 109 without patterning. Thereafter, the pixel defininglayer 111 is formed by patterning the deposited material, and thepassivation layer 109 is formed by patterning using the pixel defininglayer 111 as a mask. When the deposited material used to form thepassivation layer 109 is patterned, the edge of the pixel defining layer111 is also partially etched out, so that the width of the pixeldefining layer 111 is reduced and the pixel defining layer 111 does notoverpass the edge of the passivation layer 109.

Thereafter, referring to FIG. 2I, the intermediate layer 112 and thesecond electrode 113 are formed on the first electrode 110, therebyfinally manufacturing the organic light emitting display apparatus 100.The intermediate layer 112 includes an organic emission layer (notshown) that emits visible light. The intermediate layer 112 may beformed by using any of various methods, for example, a printing method.In detail, the intermediate layer 112 may be formed by using an inkjetprinting method.

A plasma surface-processing process may be performed before theintermediate layer 112 is formed. In other words, the upper surface ofthe first electrode 110 and the exposed surface of the pixel defininglayer 111 may be plasma-processed. Accordingly, contact between theintermediate layer 112 and the first electrode 110 is improved.

The intermediate layer 112 is spaced and separated from the pixeldefining layer 111 by the passivation layer 109. In particular, theintermediate layer 112 is more effectively separated from the pixeldefining layer 111 by using the plasma processing on the surface of thepixel defining layer 111.

The edge region 112 a of the intermediate layer 112 is spaced apart fromthe first electrode 110. In other words, the protrusion 109 a of thepassivation layer 109 is disposed between the edge region 112 a of theintermediate layer 112 and the first electrode 110, so that the edgearea 112 a is separated from the first electrode 110.

The second electrode 113 is formed on the intermediate layer 112. Thesecond electrode 113 may be formed on the entire regions of theintermediate layer 112 and the pixel defining layer 111. When a voltageis applied via the first electrode 110 and the second electrode 113, theorganic emission layer of the intermediate layer 112 emits visiblelight.

Although not shown in FIG. 2I, a sealing member (not shown) may bedisposed on the second electrode 113.

In the method of manufacturing the organic light emitting displayapparatus 100 according to the present embodiment, the edge region 112 aof the intermediate layer 112 is separated from the first electrode 110via the extension 109 a of the passivation layer 109. Accordingly, theedge region 112 a of the intermediate layer 112 is separated from thefirst electrode 110, so that the edge region 112 a of the intermediatelayer 112 is prevented from having abnormal electrical characteristics.Consequently, the entire region of the intermediate layer 112 mayprovide a uniform image quality.

In addition, since the passivation layer 109 is formed throughpatterning by using the patterned pixel defining layer 111 as a maskwithout needing a special mask, the convenience of a process isimproved.

Moreover, in the method of manufacturing the organic light emittingdisplay apparatus 100 according to the present embodiment, since thefirst electrode 110 is formed on the substrate 101, the visible lightgenerated by the intermediate layer 112 is recognized by a user withoutbeing lost due to interference, resonance, or the like. Thus, the imagequality of the organic light emitting display apparatus 100 is improved.In particular, when the organic light emitting display apparatus 100 isa bottom emission type apparatus, the improvement of the image qualitycan be significant.

In addition, the pixel defining layer 111 is formed to have a widthsmaller than that of the passivation layer 109 so as not to extendbeyond the edge of the passivation layer 109. The pixel defining layer111 is spaced apart from the first electrode 110. Accordingly, badpatterning and non-uniform formation of the intermediate layer 112 areprevented. In other words, when the intermediate layer 112 is formed onthe first electrode 110 during patterning of the intermediate layer 112,the intermediate layer 112 is easily prevented from being formed even onthe upper surface of the pixel defining layer 111.

In a display panel, for example, when an intermediate layer contacts alateral surface of a pixel defining layer, a difference between thethicknesses of a portion close to the pixel defining layer and a portionspaced away from the pixel defining layer among the region of theintermediate layer increases. Thus, improvement of emission propertiesis not easy due to the non-uniform thickness of the intermediate layer.In particular, when the surfaces of an first electrode and the pixeldefining layer are processed using plasma or the like before theformation of the intermediate layer, formation of the intermediate layeron the upper surface of the pixel defining layer may be prevented, butthe non-uniformity of the thickness of the intermediate layer increases.

However, in embodiments of the present invention, the pixel defininglayer 111 is disposed on the upper surface of the passivation layer 109and the intermediate layer 112 is spaced apart from the pixel defininglayer 111, thereby preventing the thickness of the intermediate layer112 from being non-uniform. In particular, the passivation layer 109contains an inorganic material, and thus more easily contacts theintermediate layer 112 than the pixel defining layer 111.

An organic light emitting display apparatus and a manufacturing methodthereof according to embodiments of the present invention can easilyimprove image quality characteristics.

While embodiments of the present invention has been particularly shownand described, it will be understood by those of ordinary skill in theart that various changes in form and details may be made therein withoutdeparting from the spirit and scope of the present invention as definedby the following claims.

What is claimed is:
 1. An organic light emitting display apparatuscomprising: a substrate comprising a major surface; a thin filmtransistor disposed over the major surface of the substrate and havingan active layer; a passivation layer formed over and enclosing the thinfilm transistor; a pixel defining layer formed over the passivationlayer; a first electrode disposed over the major surface of thesubstrate and electrically connected to the thin film transistor; anorganic emission layer disposed over the first electrode; a secondelectrode disposed over the organic emission layer, wherein the organicemission layer and the pixel defining layer do not overlap when viewedin a direction perpendicular to the major surface, and wherein thepassivation layer further includes at least one protrusion extendinglaterally away from the thin film transistor and directly on the firstelectrode.
 2. The organic light emitting display apparatus of claim 1,wherein an edge region of the organic emission layer is separated fromthe first electrode.
 3. The organic light emitting display apparatus ofclaim 1, wherein the passivation layer comprises an inorganic material.4. The organic light emitting display apparatus of claim 1, wherein thepassivation layer comprises an oxide or a nitride.
 5. The organic lightemitting display apparatus of claim 1, wherein the pixel defining layercomprises an organic material.
 6. The organic light emitting displayapparatus of claim 1, wherein the pixel defining layer has a widthsmaller than that of the passivation layer so as not to overpass an edgeof the passivation layer.
 7. The apparatus of claim 1, wherein a portionof the passivation layer is interposed between the organic emissionlayer and the pixel defining layer.
 8. The apparatus of claim 1, whereinthe at least one protrusion of the passivation layer is interposedbetween the organic emission layer and the first electrode.
 9. Theapparatus of claim 1, wherein the passivation layer enclosing the thinfilm transistor does not extend between the thin film transistor and thesubstrate.
 10. The organic light emitting display apparatus of claim 1,wherein the first electrode contacts the substrate.
 11. The organiclight emitting display apparatus of claim 1, wherein the first electrodeis in direct contact with the substrate.
 12. The organic light emittingdisplay apparatus of claim 11, wherein the organic light emittingdisplay apparatus is a bottom emission type light emitting displayconfigured to transmit light generated from the organic emission layerthrough the substrate.
 13. The organic light emitting display apparatusof claim 1, wherein: the thin film transistor further comprises a gateelectrode insulated from the active layer, a source electrode, and adrain electrode; and the first electrode is electrically connected tothe drain electrode.
 14. The organic light emitting display apparatus ofclaim 13, further comprising: a gate insulating layer is disposedbetween the active layer and the gate electrode, and an interlayerinsulating layer is disposed between the gate electrode and the sourceelectrode and between the gate electrode and the drain electrode; andwherein the gate insulating layer and the interlayer insulating layerare covered with the passivation layer without extending beyond theboundary of the passivation layer.
 15. The organic light emittingdisplay apparatus of claim 13, wherein the drain electrode and the firstelectrode are connected to each other by a connection portion.
 16. Theorganic light emitting display apparatus of claim 15, wherein theconnection portion is formed of a material same as the material used toform the source electrode or the drain electrode.